Electronic timepiece

ABSTRACT

An electronic timepiece having an intermittent driving means for rotating the second hand step by step, in which the second hand may be driven in two or more ways, one of by a large step as driving the second hand at the rate of one step per second and the other is by a small step such as driving the second hand at the rate of ten steps per second. There is provided a large step driving pulse producing circuit, a small step driving pulse producing circuit, a transducer for transducing the pulse into the rotating motion, a large step transmitting means, a small step transmitting means, a train for transmitting the rotating motion to the second hand, and means for changing the pulses applied to the transducer and for changing the transmitting means.

BACKGROUND OF THE INVENTION

The present invention relates to an electronic timepiece having anintermittent driving means for rotating the second hand step by step.

In the electronic timepiece, an intermittent driving means such as astep or pulse motor is preferably employed because such a motor may beoperated with a small power consumption and may securely drive thesecond hand against the shock given thereto, although it is desirable todrive the second hand continuously to indicate the flow of time. In suchan intermittent drive electronic timepiece, the second hand is driven atthe rate of one step per second. However, in order to set precisely thesecond hand to less than a time or to read an error of the second at atime, the timepiece must be constructed to indicate the time in an orderbelow a second such as the order of 1/10 second.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an electronictimepiece in which the second hand may be driven with a step smallerthan that of a second to indicate the time with greater accuracy thansecond steps will give.

Another object of the present invention is to provide an electronictimepiece in which the use of a large step of the second hand such asone step per second and the use of a small step such as ten steps persecond may be selectively changed.

In accordance with the present invention there is provided an electronictimepiece comprising a large step driving pulse producting circuit, asmall step driving pulse producing circuit, means for transducing saiddriving pulse into the rotating motion, means for changing said drivingpulses to be applied to said means for transducing, means fortransmitting the rotating motion by said large step driving pulse, meansfor transmitting the rotating motion by said small step driving pulse,means for changing said means for transmitting the rotating motion, atrain for transmitting said rotating motion to second, minute and hourhands, and means for manipulating said means for changing said drivingpulses and means for changing said means for transmitting the rotatingmotion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an embodiment of the presentinvention,

FIG. 2 is a waveform of a pulse for large step driving,

FIG. 3 is a waveform of a pulse for small step driving,

FIG. 4 is a front view of a watch according to the present invention,

FIGS. 5 and 6 are plan views showing a main portion of the watch,

FIG. 7 is a sectional view showing the train of the watch, and

FIG. 8 is a block diagram of means for generating driving pulses.

Referring now to the drawings and more particularly to FIG. 1, numeral 1generally designates a main portion of the present invention. Numeral 2is a time standard signal producing means in the form of a quartzcrystal oscilator of which time standard signal is divided by thefrequency divider 3 to a predetermined frequency. The main portion 1comprises a large step driving pulse producing means 4, a small stepdriving pulse producing means 5, a driving pulse change-over means 6, afirst manipulating member 7, an electro-mechanical transducer 8, atransmission change-over means 9, a large step transmitting means 10,and a small step transmitting means 11. The large step driving pulseproducing means 4 produces an alternating pulse of 1 Hz as shown in FIG.2 and s small step driving pulse producing means 5 produces analternating pulse of 10 Hz as shown in FIG. 3. The driving pulsechange-over means 6 is actuated by the first manipulating member 7 toselect the pulse for driving the electro-mechanical transducer 8. Thetransmission change-over means 9 is also operated by the firstmanipulating member 7 to select the transmitting means. The large steptransmitting means 10 is constructed to transmit the output power of thetransducer 8 to the train to drive the second hand (hereinafterdescribed) at the rate of one step per second and the small steptransmitting means 11 is constructed to transmit the output power of thetransducer 8 to the train to drive the second hand at the rate of tensteps per second.

The train comprises a fourth gear 12, a third wheel 13, a center wheel14 mounting a minute hand 15, a minute wheel 16, and an hour wheel 17carrying an hour hand 18, as usual watch.

In this embodiment, a mechanism for a chronograph is provided. Themechanism comprises a clutch means 19, a second manipulating member 20,a second arbor 21 carrying a second hand 22 also serving as achronograph second hand, an intermediate wheel 23, and a chronographminute wheel 24 carrying a chronograph minute hand 25. The clutch means19 is actuated by the second manipulating member 20 to transmit therotation of the fourth gear 12 to the second arbor 21. The intermediatewheel 23 acts to transmit the rotation of the center wheel 14 to thechronograph minute wheel 24 and has a slip mechanism which acts to slipwhen the chronograph minute hand 25 is returned to zero. The chronographminute wheel 24 has a heart cam mechanism not shown which is actuated bya third manipulating member 26 to return the chronograph minute hand tozero. As hereinafter described in detail, the second arbor 21 has aheart cam mechanism.

Referring to FIG. 4, the watch according to the embodiment has thechronograph minute hand 25, the common second hand 22, the ordinary hourhand 18 and minute hand 15. The first manipulating member 7 may beshifted to three axial positions 7a, 7b, and 7c. In the innermostposition of 7a, the second hand 22 rotates one step per second which isrepresented by a distance between the indexes 29. The second hand 22rotates ten steps per second in the intermediate position 7b. When themember 7 is pulled to the outermost position 7c, the second hand 22stops and the hour hand 18 and minute hand 15 may be rotated bymanipulating the member 7 to correct the time display with the wellknown mechanism. The second manipulating member 20 is manuallydepressible and means is provided for alternatively rotating andstopping the second hand 22 and minute hand 25 at every depression ofthe member 20 as will be described hereinafter. The second hand 22 andminute hand 25 may be returned to zero by depressing the thirdmanipulating member 26.

Referring to FIG. 5 which shows an ordinary operating state of thewatch, the first manipulating member 7 is held in the innermost position7a by engagement of the well known setting lever 51 with setting leverspring 52. The divider 3, large and small step driving pulse producingmeans 4 and 5, and driving pulse change-over means 6 are constructedinto an integrated circuit 63. A resilient switch blade 53 is providedto be insulated and connected to the driving pulse change-over means 6.The resilient switch blade is positioned adjacent the end portion 51a ofthe setting lever 51. The driving pulse change-over means 6 is soarranged that, when the end portion 51a contacts with the switch blade53, the driving pulse such as 10 Hz pulse shown in FIG. 3, which isproduced in the small step driving pulse generator 5, is applied to thedriving coil 54 of the electro-mechanical transducer 8, and when the endportion 51a removes from the switch blade 53, the driving pulse such as1 Hz pulse shown in FIG. 2, which is produced in the large step drivingpulse generator 4, is applied thereto.

The electro-mechanical transducer 8 such as pulse motor comprises arotor 55 (FIG. 7) of permanent magnet and a pinion 55a integral with therotor. The pinion 55a has ten teeth and engages with a change gear 56having twelve teeth. The change gear 56 is pivotally mounted on a changelever 57 which is adapted to be rocked about a pin 58 by actuation ofthe setting lever 51 with the cooperation of the pin 51b on the settinglever with the cam groove 57a of the change lever 57. A sixth wheel 59engaging with an intermediate gear 70 constitutes a part of the smallstep transmitting means 11 and has sixty teeth. The sixth wheel isintegral with a sixth wheel pinion 59a having six teeth which engageswith a fifth wheel 60. The fifth wheel 60 constituting a part of thelarge step transmitting means 10 has sixty teeth and is integral with afifth wheel pinion 60a having ten teeth. The fifth wheel pinion 60aengages with the fourth gear 12 having fifty teeth which is integralwith a fourth pinion 12a as shown in FIG. 7. The fourth pinion 12a isrotatably mounted on the second arbor 21 which is rotatably supported bynot shown bearings. Secured to the second arbor 21 is a heart cam 21a towhich a star shaped spring washer 21d forming a part of the clutch means19 is secured. The outer ends of legs of the washer are secured to anengaging ring 21b which is slidably provided on the fourth gear 12. Thespring washer 21d urges the engaging ring 21b toward the fourth gear 12transmit the rotation of the fourth gear to the second arbor 21.

U-shaped disengaging lever 61 is secured to a not shown base plate atthe base portion 61a as shown in FIG. 5. The disengaging lever has apair of arms 61b extending to radially opposite sides of the engagingring 21b and a pair of projections 61c located at the radially oppositesides of an indexing wheel 62. The indexing wheel 62 is pivotallymounted on the base plate with a shaft 66 and comprises a cam plate 62cengaging with the projections 61c and a ratchet 62b engaging with anindexing end 64d of a starting lever 64. The starting lever 64 issecured to the base plate at an end 64a and has a resilient portion 64b,a slot 64c engaging with a pin 65 secured to the base plate and an end64e engaging with the inner end of the second manipulating member 20(shown in FIG. 4). Depressing the second manipulating member 20, the end64d indexes the ratchet 62b and cam plate 62a one step. When the fingerof the operator removes from the member 20, the starting lever 64returns to the position of FIG. 5 where the lower end of the slot 64cengages with the pin 65. It will be seen that the end 64d acts also as alocating member for the ratchet 62b, which is advantageous to themanufacture of the mechanism within a small space with a small number ofparts.

When each of the projections 61c of the disengaging lever 61 engageswith the top 62c of the cam plate 62a of the indexing wheel 62 as shownin FIG. 5, arms 61b are removed from the engaging ring 21b as shown inFIG. 7. When the projection 61c removes from the top 62c as shown inFIG. 6, arms 61b are biased to the engaging ring 21b by the resilientforce in the portions 61d, so that the arms engage with tapered surface21c of the engaging ring to take off the ring from the fourth gear 12resulting in the stop of rotation of the second arbor 21.

A hammer 67 secured to the base plate at an end 67a comprises aresilient portion 67b, a projection 67c engaging with the end of thethird manipulating member 26 (shown in FIG. 4), and an actuating slant67d. When the third manipulating member 26 is depressed, the hammer 67is biased so that the actuating slant 67d engages with the heart cam 21to rotate it and hence to return the second hand to zero.

In operation, assume that the first manipulating member 7 is positionedin the innermost position 7a in FIG. 4. With reference to FIG. 5, 1 Hzdriving pulse is applied to the coil 54, so that the pinion 55a rotatesone full turn at the rate of two steps per 2 second. The rotationalspeed of the pinion 55a is reduced by the train comprising the gear 56,fifth wheel 60 and fifth wheel pinion 60a to rotate the fourth wheel 12at the rate of 60 step per minute. At this time, the sixth wheel pinion59a and sixth wheel 59 idle. Rotation of the fourth wheel 12 istransmitted to the second arbor 21 and second hand 22 through theengaging ring 21b, spring washer 21d and heart cam 21a, so that thesecond hand rotates at the rate of one step per second.

Pulling out the first manipulating member 7 to the intermediate position7b of FIG. 4, the setting lever 51 is counterclockwisely rotated aboutthe pin 51c, and the pin 51d is moved from the notch 52a of the settinglever spring 52 to the notch 52b as shown in FIG. 6. Rotation of thesetting lever causes the change lever 57 to rotate clockwisely about thepin 58 to disengage the change gear 56 from the fifth wheel 60 to engageit with the gear 70. The end 51a of the setting lever 51 engages withthe switch blade 53 to apply the signal to the driving pulse change-overmeans 6, whereby 10 Hz pulse is applied to the coil 54. Thus, the pinion55a rotates at the rate of 2 steps per 0.2 second. Rotation of thepinion 55a is transmitted to the fourth gear 12 via the train comprisingthe gears 56, 70 sixth wheel 59, sixth wheel pinion 59a, fifth wheel 60and fifth wheel pinion 60a, so that the second hand 22 may be rotated atthe rate of ten steps per second.

Pulling out the first manipulating lever 7 to the outermost position 7c(FIG. 4), the setting lever 51 is rotated to the dotted line position51g of which rotation does not effect the rotation of the change lever57 because the cam groove 57a of the region has a circular cam face withthe pin 51c for its center. Supply of the pulse to the coil 54 is cutoff by operation of a switch (not shown) and the second hand 22 isstopped by operation of a brake mechanism (not shown), of which detailedexplanation is omitted since the mechanism is well known. Under thiscondition, the hour hand 18 and minute hand 15 may be rotated torotating the first manipulating member 7 for the correction of the timedisplay.

Now describing the chronograph operation, two kinds of chronographoperations may be performed in the illustrated watch, one of which iscarried out with the large step driving pulse and the other is carriedout with the small step driving pulse. Since both operations are similarto each other, the latter case will be described hereinafter. Asmentioned above, when the first manipulating member 7 is located in theintermediate position 7b, the change gear 56 engages with the sixthwheel 59 as shown in FIG. 6 and the second arbor 21 is rotated at therate of 600 steps per minute. Depressing the second manipulating member20, the starting lever 64 is biased in the direction of the arrow 64g torotate the ratchet 62b and cam plate 62a one step in thecounterclockwise direction. Thus, projection 61c removes from the top62c of the cam plate, so that the arms 61b engage with the taperedportion 21c of the engaging ring 21b resulting in removal of theengaging ring from the fourth gear 12. Accordingly, the second arbor 21and second hand 22 step upon the depression of the second manipulatingmember 20. Thereafter, when the third manipulating member 26 isdepressed, the slant 67d of the hammer 67 engages with the heart cam 21ato rotate it together with the second hand 22 to the zero position withsliding the tapered portion 21c of the engaging ring 21b on the side ofeach arm 61b.

Depressing again the second manipulating member 20, the starting lever64 acts to rotate the ratchet 62b and cam plate 62a one step, resultingin the engagement of the projection 61c with the top 62c of the camplate 62a. Thus, the arms 61b removes from the engaging ring 21c toengage the ring with the fourth gear 12 to rotate the second hand. Theminute wheel 24 may be returned to zero by not shown mechanism similarto the above described mechanism by depressing the third manipulatingmember 26.

While a single embodiment of the present invention has been illustratedand described, it will be apparent to those skilled in the art thatnumerous variations and modifications may be made. For example, changeof the steps of the second hand may be performed other mechanism thanthe axially moved manipulating member 7 as rotational mechanism, thechange gear may be axially moved to change the engagement with axiallyarranged fifth and sixth wheels and three or more kinds of driving stepmay be employed to drive the second hand. It is preferable to design thedriving pulse change-over means 6 to have time delay corresponding tothe changing operation of the change lever 57 and change gear 56. Theintermediate gear 70 may be omitted, if an electro-mechanical transduceris so arranged that the rotor 55 may be reversely rotated by a smallstep driving pulse.

Referring to FIG. 8 showing an example of means for generating largestep and small step driving pulses and means for changing the drivingpulses, numeral 101 designates a quartz crystal oscilator producing thetime standard signal of 30720 Hz which may be advantageously dividedinto 10 Hz and 1 Hz pulse signals. The time standard signal is appliedto a frequency divider 102, which includes a gate circuit 103 having 1/3divisional rate. The gate circuit 103 produces 80 Hz pulse signal bydividing the output of seventh flip-flop Q7 by 3. The 80 Hz pulse signalis applied to a second frequency divider 104 including a gate circuit105. The gate circuit has 1/10 divisional rate and hence the secondfrequency divider 104 has 2⁻³ ×10⁻¹ divisional rate. Thus, the flip-flopQ12 produces 10 Hz pulse signal for the small step driving and the gatecircuit produces 1 Hz pulse signal for the large step driving. Numeral106 is a reset switch, 108 is a change-over switch for large and smallsteps, 107 is a reset signal generating circuit comprising a guardcircuit for opening operation of the switch 106, and a date-inputflip-flop for reading the state of the switch using 40 Hz signal fromthe flip-flop Q10 of the frequency divider 104 for clock pulse. Theguard circuit comprises a pullup resistor, an invester and a transistor109 is a change-over signal generating circuit having similarconstruction as the circuit 107.

Numeral 110 is a gate circuit for producing the small step driving pulseφ10 of 10 Hz. When the first manipulating member 7 is pulled out to theintermediate position 7a (FIG. 4), the switch 108 corresponding thedriving pulse change-over means 6 is closed and the output of thechange-over signal generating circuit 109. is zero. Accordingly, theoutput pulse is

    φ10=Q.sub.10 ·Q.sub.11 ·Q.sub.12

which means that negative pulse of 10 Hz having the width of 1/80 secondis produced by the gate circuit 110. 111 is a gate circuit for producingthe large step driving pulse φ1. The pulse is

    φ1=Q.sub.10 ·Q.sub.11 ·Q.sub.12 ·Q.sub.13 ·Q.sub.14 ·Q.sub.15 ·Q.sub.16.

That is the negative pulse of 1 Hz having the width of 1/80 second isproduced. Both pulses φ10 and φ1 are combined by an AND gate 112 toproduce a signal φ. The signal φ acts to trigger a toggle flip-flop 113.The signal φ and output Q and Q of the flip-flop 113 are applied to adriving circuit 114, which in turn produces alternative output pulse todrive the pulse motor 115 corresponding the electro-mechanicaltransducer 8. The reset signal from the reset signal generating circuit107 is applied to the second frequency divider 104 through the gate 116and inverter 117 to change the output of Q11-Q16 to zero.

From the foregoing it will be understood that the present inventionprovides an electronic timepiece in which second hand may be driven stepby step with a small step on demand, whereby it is possible to setprecisely the second hand to the time and to read accurately the time.

What is claimed is:
 1. An electronic timepiece comprising: display meanshaving a plurality of hands for displaying time;first means forproducing a first pulse train of a first predetermined frequency; secondmeans for producing a second pulse train of a second predeterminedfrequency less than said first predetermined frequency; switch means forselecting one of said first or second pulse trains and providing theselected pulse train at its output; an electro-mechanical transducer forconverting said selected pulse train into rotary motion; transmissionmeans for transmitting the rotary motion of said electro-mechanicaltransducer to said hands of said display means, said transmission meanshaving first and second drive ratios; and means for changing said driveratio of said transmission means in response to the change in saidselected pulse train by said switch means.
 2. The electric timepiece ofclaim 1;wherein said first means includes a quartz oscillator forproducing a high frequency time standard signal, and first divider meansfor reducing the frequency produced by said quartz oscillator to saidfirst predetermined frequency; and wherein said second means includessecond divider means for reducing said first predetermined frequency tosaid second predetermined frequency.
 3. The electronic timepiece ofclaim 5 wherein said display means includes:an hour hand; a minute hand;and a second hand.
 4. The electronic timepiece of claim 3 furthercomprising:clutch means connected between said transmission means andsaid second hand to disconnect said second hand from said transmissionmeans; means for controlling the engagement of said clutch means toselectively disconnect said second hand from said transmission means inresponse to user command; and means for resetting said second hand inresponse to a user command.
 5. The electronic timepiece of claim 4wherein said second hand is used as both an actual time second hand andas an elapsed time second hand;wherein said means for resetting isactuated to reset said second hand after said clutch means is disengagedby said means for controlling, to disconnect said second hand from saidtransmitting means; and wherein said clutch means is engaged by saidmeans for controlling after said second hand is reset to being theelapsed time function.
 6. The electronic timepiece of claim 4 whereinsaid means for resetting includes a heart cam and a user activatedhammer for rotating said heart cam to move said second hand to the zeroposition.
 7. The electronic timepiece of claim 4 wherein saidelectro-mechanical transducer converts said selected pulse train intointermittent rotary motion.